Dashboard indicator module formed by a motor and electrical connection means

ABSTRACT

The present invention relates to a dashboard indicator module comprising, in a casing, a rotary motor, an output shaft, mechanical reduction means associated with the motor, at least one electrical supply coil, electrical connection tabs linked to the coils leaving said casing and electrical contact elements, characterised in that said electrical contact elements can be fitted on the connection tabs in order to produce solderless connectors on the printed circuit or even removed from the connection tabs in order to allow the connection tabs of the motor to be soldered directly to the printed circuit.

The present invention relates to the field of motor vehicle dashboard indicators and is more particularly composed of a module consisting in a motor and electrical connection means, so-called connectors or contacts, intended to be fixed on a printed circuit which includes all the electronic components required for the operation of the motor.

Generally, dashboard pointers (tachymeter, gauge) for motor vehicles are actuated by so-called step by step electromagnetic motors. Such motors are for example disclosed in patent FR 2742940 or patent FR 2859323. Such motors are fixed behind the dashboard on a printed circuit on which the electrical supply tracks and all the electronic components intended to operate the motor are fixed. The printed circuit is fixed in the dashboard instrument and the motor is fixed to the printed circuit. The electric connection of the motor is generally carried out through the soldering of electric connection tabs integral with the motor together with the printed circuit tracks. Soldering the connectors to the printed circuit and positioning the motor connection tabs in such connectors can also be considered. Patent FR 2885739 of the applicant discloses a method of this type.

Nevertheless, all the prior art methods have some disadvantages:

-   -   The connectors must be positioned on the printed circuit on the         one hand and the casing containing the motor must be positioned         on the printed circuit on the other hand. Thus, the connectors         must be positioned on the printed circuit and then the casing         must be positioned on the printed circuit and the casing must be         connected to the connectors.     -   Such prior art techniques do not allow the easy removal and         reutilization of the motor on another printed circuit with the         same electric connection means in a simple and immediate way.

Solutions already exist in the prior art showing motors provided with curved shapes and deformable connection tabs. Upon the positioning of the motor on the printed circuit, such particular connection tabs come in contact with electric contact surface areas on the printed surface and thus get deformed in order to provide the electric contact. Thus, the motor is not soldered onto the circuit.

However, such solutions require the provision of an original motor solution which must have very special connection tabs. This requires a different product in parallel with a conventional solution with a motor having straight connection tabs and requiring solders on the printed circuit. Depending on the application or the targeted client, the production tools are doubled and manufacturing the assembly of two motors is expensive.

The invention intends to remedy this problem while claiming an electric motor module which can as well be used with the connection tabs being soldered on the printed circuit or with solderless connectors using contacts added onto the connection tabs, as a function of the type of connection requested by the client.

More particularly, the object of the present invention consists in providing a dashboard indicator module including, in a casing, a rotary motor, an output shaft, mechanical reduction means associated with the motor, at least one electric supply coil, electric connection tabs associated with the coils leaving said casing and electric contact elements, characterised in that said contact elements can be fitted on the connection tabs in order to provide solderless connections to the printed circuits or will be removed from the connection tabs in order to allow the connection tabs of the motor to be directly soldered to the printed circuit.

Another object of the invention consists in providing electrical contact elements composed of a first part in mechanical and electrical connection with said tabs and a second free part intended to come in mechanical and electrical contact with a voltage-supplied surface of a printed circuit which supports said module and is used for supplying said motor with voltage.

Another object of the present invention consists in providing a module including a motor and electric contacts integral with the motor which does not require the motor being soldered to a printed circuit nor any soldering at the level of the printed circuit between the motor and said circuit and allowing the easy removal of the motor positioned on the printed circuit.

Another object of the present invention also consists in providing a module including a motor, electrical contacts and mechanical rivets which are totally independent of the printed circuit and can adapt to several printed circuit of different natures.

Thus, the printed circuit intended to receive the indicated module described by the invention only has to provide electrical or mechanical fastening means and just has to provide, in addition to the electrical components required for steering the motor, holes so as to enable the passage of the electrical and mechanical contacts of the module.

In practice, the motor provides conventional electrical connection tabs in the form of axes or pins and electrical contacts which are mechanically fixed or countersunk on such tabs. Soldering such contact with tabs can also be considered.

The shape of the electrical contacts can be any shape for example a spiral shape, but they must include a first part ensuring the electric contact of such element with the motor connection tab and a second part oriented towards the printed circuit to set a link with the electrical connection area of the printed circuit. The shape of this contact must also allow the deformation thereof upon the positioning of the motor on the printed circuit.

The mechanical retaining of the motor on the printed circuit can be provided by well-known deformable rivets in the prior art documents or by any other method which can be use by the person skilled in the art.

Upon the mechanical fastening of the motor, the electrical contact elements deform and act as a spring. When balanced in compressed position, a force is thus applied onto the printed circuit and onto the motor casing. Since the rivets provide the mechanical retaining of the motor on the printed circuit, this force applied by the spring thus provides an electric contact of good quality.

Thus, we have a motor module+a reliable and independent electrical contact which can adapt to various printed contacts and which can be positioned and removed on or from the printed circuit anytime.

Ideally but in a non limitative way, the motor can provide cavities close to the electrical connection tabs in order to allow the positioning of the lower face of the motor casing onto the printed circuit. The module can also have pads whereon the motor rests. With either solution, the motor is thus fixed in a stable way to the printed circuit and will be insensitive to possible vibrations in operation.

Understanding the invention will be easier while referring to the appended drawings in which:

FIG. 1 shows a cross-sectional view of a prior art module,

FIG. 2 shows an exemplary module according to the invention, formed of a motor in its casing and electrical contacts associated with the motor connection tabs,

FIG. 3 shows a printed circuit intended to receive the module shown in FIG. 2,

FIG. 4 shows an exemplary electrical contact used in the module of the invention in a non deformed condition,

FIG. 5 shows an exemplary electrical contact used in the module of the invention according to FIG. 3 in a deformed condition,

FIG. 6 shows a top view of the module where the contact shown in FIGS. 4 and 5 is fixed on an electrical connection tab of the motor,

FIG. 7 shows another exemplary electrical contact used in the module of the invention in a non deformed condition,

FIG. 8 shows another exemplary electrical contact used in the module of the invention according to FIG. 7 in a deformed condition,

FIG. 9 shows another exemplary electrical contact used in the module of the invention,

FIG. 10 is a cross-sectional view of a module according to the invention including contacts as shown in FIGS. 4, 5 and 6 close to a printed circuit,

FIG. 11 is a cross-sectional view of a module according to the invention including contacts as shown in FIGS. 4, 5 and 6 in contact with a printed circuit,

FIG. 12 is a cross-sectional view of a module according to the invention including contacts as shown in FIGS. 7 and 8, close to a printed circuit,

FIG. 13 is a cross-sectional view of a module according to the invention including contacts as shown in FIGS. 7 and 8 in contact with a printed circuit,

FIG. 14 is a cross-sectional view of a module according to the invention including contacts as shown in FIG. 9 close to a printed circuit,

FIG. 15 is a cross-sectional view of a module according to the invention including contacts as shown in FIG. 9 in contact with a printed circuit,

FIG. 16 is a printed circuit intended to receive a module according to the invention ensuring contacts as shown in FIG. 9,

FIGS. 17 a and 17 b show another exemplary electrical contact used in the module of the invention,

FIG. 18 is a cross-sectional view of a module according to the invention including contacts as shown in FIGS. 17 a and 17 b close to a printed circuit,

FIG. 19 is a cross-sectional view of a module according to the invention including contacts as shown in FIGS. 17 a and 17 b in contact with a printed circuit.

FIG. 1 shows an embodiment of the prior art. It includes a motor of the electromagnetic type for example, in a casing 7 b and shows electrical connection tabs 14 associated with the motor coils, having a non linear form and here having a J-shape. This motor is intended to be fixed on a printed circuit and such connection tabs 14 to get deformed to provide a reliable electrical contact with such printed circuit. However, this embodiment requires a product which is much different from this one, this more conventional one and using straight connection tabs which must be soldered to the printed circuit. Thus, according to one or the other utilization, two modules must be produced independently.

FIG. 2 shows a module 1 according to the invention. It is composed of a clamped plastic casing 7 containing typically an electromagnetic motor, and a set of reducer gears moving in rotation on an axis 6 for example, a hollow axis intended to receive a pointer. Such pointer will be used for giving, on the dashboard of a motor vehicle, information on the speed, a level or any other parameter. This casing 7 preferably includes two deformable rivets 5 which are used for the mechanical behavior of the casing 7 on the printed circuit 8 intended to receive it. It also includes resting pads 4 on which the module 1 rests on the printed circuit 8 and the conventional straight electrical connection tabs 3. Such connection tabs 3 are in fact the electrical connections of the coils of the electromagnetic motor inside the casing 7 and are thus for example for a two-coil, two phase motor in the form of two pairs of tabs 3. Electrical contacts are mechanically countersunk or soldered are fixed on such tabs. This module 1 is intended to be positioned on a printed circuit 8 as shown in FIG. 3. When removing the contacts 2 of the tabs 3, the module 1 can also be connected to the printed circuit 8 while directly soldering the tabs 3 to the printed circuit 8.

Typically, such printed circuit 8 shows, in addition to all the electronic elements required for driving the motor, a first series of holes 9 intended to receive the deformable mechanical rivets 5. Once such rivets 5 are positioned through the holes 9, they are deformed to provide the solid retaining of the module 1 on the printed circuit 8. This circuit 8 also shows a second series of holes 10 intended to receive the electrical connection tabs 3. The latter go through the holes 10 without any physical contact. Contact surface areas 11 which receive the contacts 2 of the module 1 are positioned close to such holes. When positioning the module 1 on the printed circuit 8, the rivets 5 provide the mechanical retaining, the resting plots 4 provide the stability and the contacts 2 which preferably must have elastic properties yet deformable to provide the electrical contact between the connection tabs 3 and the contact surface area 11 through a spring effect. Without the contacts 2, the tabs 3 of the module 1 are directly soldered on the contact surface areas 11.

FIG. 4 shows a contact element 2 in a first embodiment and in a non deformable free condition. In this first embodiment, the contact 2 takes the shape of a conical and helicoidal spring and includes two significant parts. The first part 12 is intended to provide a hold to the connection tab 3, either through mechanical countersinking or through soldering.

The second part 13 is intended to provide the electrical contact with the contact surface area 11 of the printed circuit 8.

During the positioning of the module 1 on the printed circuit 8, this contact 2 gets deformed and thus provides the quality of the electric contacts in the printed circuit and the motor of the module 2 through the action and reaction forces.

FIG. 5 shows the very same module 2 according to FIG. 4 but in a deformed condition as it must be after the assembling of the module 2 on the printed circuit 8. The second part 13 must then be in contact with the contact surface area 11 of the printed circuit 8 and the windings of the contact 2 are then placed closer to each other, possibly in a joint winding configuration.

When the contact 2 is provided on the connection tab 3, the association tab 3+contact 2 can be seen under the module as in FIG. 6. The connection tab 3 is in physical contact with the contact element 2 at the level of the first part 12 previously described.

FIG. 7 shows a contact element 2 in a second embodiment. It must preferably be have like all the embodiments, elastic properties and have two distinct parts 12 and 13 intended to come respectively in contact with the connection tab 3 of the motor and with the electrical contact surface area 11 of the printed circuit 8. In this FIG. 7, the contact element 2 is in a non deformed free condition. FIG. 8 shows this same contact element 2 in a deformed condition as it must be after the assembling of the module on the printed circuit.

FIG. 9 shows a contact element in a third embodiment with the same two characteristic parts 12 and 13 required for the correct operation of the contact.

FIGS. 10 and 15 show cross-sectional views of the module close to, or in contact with, the printed circuit.

In FIGS. 10, 12 and 14, the module is close to the printed circuit 8 prior to be fitted. The contact 2 is positioned to be integral with the connection tab 3 and this tab 3 starts going through the hole 10 of the printed circuit 8.

In FIGS. 11, 13 and 15, the module is fitted on the printed circuit 8. The rest pads 4 are in contact with the printed circuit 8 and the contact elements 2 are in deformed condition and provide the quality of the electrical supply of the motor through the mechanical powering on of such contact elements 2.

When removing the contacts 2 from the tabs 3, the latter can then be directly soldered to the printed circuit 8.

FIG. 16 shows the printed circuit 8 intended to receive the contact element 2 in the third embodiment shown in FIGS. 9, 14 and 15.

The same elements as in the printed circuit shown in FIG. 3 can be found as is intended to receive the contact elements in the first and second embodiments. The relative position of the holes 10 for the passage of the tabs 3 and complex surface areas 11 make the difference between the printed circuits of FIGS. 3 and 16. On the printed circuit of FIG. 3, the holes 10 are in the middle of the contact surface area 11 through the configuration of the contact elements 2 in the first and second embodiment, whereas the printed circuit 8 of FIG. 16 shows holes 10 which are besides the contact surface area 11 through the contact elements 2 configuration in the third embodiment.

FIGS. 17 a and 17 b show another example of an electric contact 2 in a tubular form showing an easy soldering on the printed circuit 8, where a first part 12 intended to come in contact with the connection tab 3 through a spring effect can be found as well as a second part 13 providing the electronic contact with the printed circuit 8 in the form of wings, the number of such wings varying and having various forms as can be seen in FIGS. 17 a and 17 b.

FIG. 18 shows this contact 2 fitted on an electric connection tab 3 in a cross-sectional view showing it close to the printed circuit 8.

FIG. 19 shows the contact 2 mounted on the electrical connection tab 3 and positioned on the printed circuit 8. The contact 2 geometry is such that it rests, thanks to the wings 13 thereof, on the one hand on the casing 7 on the upper part of the wings 13, and on the other hand on the electrical contact area 11 of the lower part thereof. The radial efforts are then suffered during the assembling of the contact 2 at the casing 7 level.

Another advantage of this contact 2 is that it can provide the electrical contact either through the contact of the wings 13 on the electrical contact areas 11 of the printed circuit 8 or through the connection of the contact body 2 inside the hole 10 which is then metallized, which makes this contact 2 as appropriate for printed circuits 8 with a simple face as with a double face.

Eventually, another advantage of this contact 2 of FIGS. 17 a and 17 b is that it is circular which ensures that the efforts caused by the micro-vibrations in operation are mainly axial efforts and not radial efforts thus making it possible for the contact 2 to provide its function over time without causing an anticipated oxidation.

The illustrations shown in this document are exemplary embodiment and in no way represent limitative embodiments. Of course, it can be considered to modify the shape of the contact elements 2 or any other element mentioned in this document without leaving the scope of the invention. 

1. A dashboard indicator module comprising, in a casing, a rotary motor, an output shaft, mechanical reduction means associated with the motor, at least one electrical supply coil, electrical connection tabs linked to the coils leaving said casing and electrical contact elements, characterised in that said electrical contact elements can be fitted on the connection tabs in order to produce solderless connectors on the printed circuit or even removed from the connection tabs in order to allow the connection tabs of the motor to be soldered directly to the printed circuit.
 2. A dashboard indicator module according to claim 1, characterised in that said contact elements have a first part in mechanical and electrical connection with said tabs and a second free part intended to come in mechanical and electrical contact with a voltage-supplied surface area of a printed circuit which supports said module and is used for supplying said motor with voltage.
 3. A dashboard indicator module according to claim 2, characterised in that said contacts have a mechanical characteristic of the spring type.
 4. A dashboard indicator module according to claim 1, characterised in that said casing has deformable rivets forming protrusions and providing the mechanical retaining of the module on said printed circuit.
 5. A dashboard indicator module according to claim 1, characterised in that said contacts are deformed upon the positioning of said module on said printed circuit.
 6. A dashboard indicator module according to claim 1, characterised in that said contact elements are mechanically fixed to the motor connection tabs.
 7. A dashboard indicator module according to claim 1, characterised in that said contact elements are soldered to the motor connection tabs.
 8. A dashboard indicator module according to claim 1, characterised in that the printed circuit has metallized holes and in that the solderless connectors are provided between the body of the contact element and the metallized holes of the printed circuit. 